Hydraulic gear shifting system



G. E. HIEBER El' AIL HYDRAULIC GEAR SHIFTING SYSTEM Aug. 20,

'Filed Aug'. 25, 19.30

4 Sheets-Sheet 1 Aug. 20, 1935. G. E. HIEBER Er AL HYDRAULIC GEAR SHIFTINCT SYSTEM 4 Sheets-Sheet 2 Filed Aug. 23, 1930 INVENTORS G. E. HIEBER ET AL HYDRAULIC GEAR SHIFTING SYSTEM Aug. 20, 1935.

4 Sheets-Sheet' 3 Filed Aug. 2:5, 1930 sion casing for lubricating the same.

Patented A ug. 20,v 1935 aoizssz mamme GEAR sms-'rma SYSTEM vGimme E. mener, Ciminna,

Hoelscher, Norwood, Ohio, assignments, to The Ciminna Cincinnati, hio, a corporachine Company, tion of Ohio aslixnombymeme tiMilling Mn- Appiimion aufm 2s, 1930, serial N o. 411,274 Y 14 owns.' (ci. 'l1-zar This invention relates to -feed or speed change transmissions and is particularly directed to a hydraulicapparatus for shifting the gears of the transmission. The apparatus of thisinvention may be applied to any transmission regardless of the number of speed changes or the nature of the mechanism to which the power is to be transmitted.

The iiuid for actuating the various devices of the apparatus may be applied or placed under pressure by any means developing sufficient power for sliding the gears into mesh. The hydraulic motive power, supplied by the duid pressure means, is controlled by the clutch shifting and gear reversing lever commonly associated with the main power shaft of the transmission. Theselection of the particular gears to be shifted is accomplished by means of a'manually adjusted valve controlling the application of the fluid under pressure to any one of a plurality of gear shifting devices located throughout the transmission. It is, therefore, a broad object of this invention to provide an improved hydraulically operated gear shifting apparatus, the various devices oftion of the-created pressure is operated coincidentally with the clutch and reversing gearing shift lever.

The fluid pressure developing means may be `of any type conveniently applied within the casing and capable of developing pressure sufcient to move the gears,A such as a constantly running pump or an impulse piston manually reciprocated to boost the pressure at the appropriate time. It is desirable in some instances to provide that the fluid supplied under pressure is a lubrieating medium such as oil, whereby the ow may be. not only to the gear shifting apparatus but to the bearings and throughout the gear transmis- I For this reason, it is another object to provide, in a systern or uid flow circuit of normally low pressure" of oil induced bythe pump,..whereby a high gear shifting pressure may be momentarily developed .within the selector valve for a gear shifting pressure impulse. Furthermore, it is an object of this invention to provide that theuid pressure source as a pump, is not continually operated against l high 4pressure loador great head pressure butv only at the time of actual gear change. It is, of `course,obvious that the lubricant supply line may be eliminated and the oil may be by-passed back Awithout utility to the reservoir during low pressure ow. @It is another object. of this invention to provide a combination [of valves arranged in the-circuit `for definitely controlling the pressure of the supplied oil for the various purposes ofthe apparatus and for controlling the selection of the particular gear shifting device to which the high pressure .impulse is directed. 4 l

It is a further ,object to. provide a device for maintaining a constant level .oi iiuid throughout .the system over a considerable period of time, so`

that there canbe no failure, of fiu'id pressure, and .for maintaining the parts in a de'nitely set relation. v

Another object is to provide an extremely compact and simple selector valve which is easily manually set at an indicated lspeed change for controlling the passage of the uid under preslsure through the valve, and which also includes a hydraulically operated device for maintaining the valve in each of its set positionsr against-accidental dispositioning. A selector valve for controlling oreii'ecting a great m'any speed changes, such as 32 in the present instance,.necessarily is of multiramose construction, although in the present instance the construction is extremely simple and the number of conduits or connections to the valve and passageways in the valve has -been reduced to' a4 minimum. .The valve is extremely small and therefore readily incorporated within the gear transmission, the same simplicity .and compactness being essentially present throughout the apparatus or system so that the gear transmission casing need be of no greater /'size than that ordinarily used.

The choke and relief valve inserted in the lubrimatically' to permit ow of fluid therethrough in either position of the control valve, and, upon the clutch valve being' initially thrown in and the power source connected with the transmission, is interposed for a moment as a choke in the line for causing the rise of pressure in the selector valve, and thereafter moves against resistance to the opposite or running position for an ultimate ow relief and re-establishing of the iiow through the by-passage, the gear shifting impulse occurring during the period of resistance or impedance to movement of the choke and relief valve. This valve is always returned to original or running ratus for this application or use. Where the shafting mounting the gears is vertically disposed as in the radial drill head, -itis necessary to provide some definite means for sustaining the gears in shifted position against the action of gravity in the event of uid pressure failure. Therefore, it is a further object of this invention to provide hydraulically operated gear shifting devices located adjacent the respective gears to be shifted which include automatically hydraulically operated means positively locking the gears in shifted position. These means may be said to be hydraulically set positions incapable of mechanical disturbance, and their disengagement can only be effected by the hydraulics controlled from the selector valve. Although set by means of fluid pressure, the fluid pressure may be entirely withpurpose of simplifying the gear shift independg ently slidable gear clusters are mounted on the same shaft for intermesh with respective adjacent gear clusters of the train. It is, therefore, another object to provide an interlock between the hydraulically operated devices moving these respective slidable gear clusters for preventing vvthe shifting of one set of gears while the other l-is in a shifted or meshing position. In other words, it is provided that one shifting device must be in neutral at all times and the shift of the other-.is dependent upon this condition existing.

Other objects relate to the general construction vof the various devices incorporated in the system and apparatus as well as their general arrangement, and these objects and other advantages will be more fully apparent from the description of the accompanying 'drawings in which:

Figure 1 is a diagrammatic lview showing the hydraulic apparatus applied to a radial drill head transmission for varying the speed of rotation of the drill spindle, the view illustrating the apparatus and system in position for imparting the f highest speed to the drill spindle.

Figures 2, 3, 4, 5, and 6 are sectional views 6 on Figure 1, these views detailing the construction of the valve and illustrating the position of the various ports of the valve when the transmission is in high speed.

Figure'lisaviewsimilarinFlgurel digrammatically illustrating lthe system and apparatus. but showing the valve and the gears in position for the lowest speed ton.

Figures 8,9, 10, 11, and 12 are sectional views taken on respective section lines 8, 9, I0, l-I, and l2 of Figure '7 illustrating the selector valve in detail and showing the disposition of the ports thereof in the low speed transmission.

Figure 13 is a sectional view taken on line l3l3, Figure-1, illustrating the means on the hydraulic system.

Figure 14 is a view on line I4--Il,

^ speed or feed change gears.

Figure 1, illustrating` in detail one of the detenta 'which are hydraulically operated for locking thev vertically mounted gears in position.

Figure -15 is a sectional view taken through that counter shaft of the transmission which carrie's the plurality of slidable gear clustersdetailing the mechanical interlock for preventing shifting of one hydraulic device when the other in shifted or. gear coupling position.

Figure 16 is a side or front view of the mechanical device illustrated in Figure l5.

Figure 17 isa view of a manually operated reciprocable piston for developing fluid pressure throughout the systemand for imparting a gear shifting impulse.

The gear shifting apparatus described in general is applied to an arrangement or train of gears within a casing, which gears may function as The present disclosure illustrates the gear train within the casing 20 of a drill head for driving the spindle of a radial drill for varying the speed of rotation thereof. The various speed changes are accomplished by shifting certain gears, slidably mounted upon splined shafts of the transmission into mesh with other gears of the train in the conventional manner.

A plurality of hydraulically shifted devices are arranged throughout the gear casing 20, each of these devices being connected to respective slidable gears of the train. An oill pump 23 or uid pressure means is disposed within the drill head casing for drawing oil from a reservoir 24 and pumping the same throughout the system asl controlled by the various devices hereinafter set forth. This oil pump may be driven from the main power shaft or any constantly driven shaft;

In this particular instance it is driven from the main power shaft 25 upon which the conventional reversing gearing and clutch are mounted.

A manually operated lbver 26 is provided vfor shifting the reversing gear control vclutch 21 on the main power shaft. This lever includes a device 28 for operating a main control valve 29 for the system, the functions of which-valve will be more apparent as the description progresses. The oilis pumped from the supply to this main control v'alve 2l through a conduit 30 at all times lwhen the main power shaft is being driven. The control lever coincidentally throws the clutch in for connecting the particular reversing gears on the driving shaft with the gear Atrain or transmission to the drill spindle 3| and operates the main control valve to open the passage for the oil to a selector valve 32. The selector valve is also manually operated for setting Ythe same at the desired indicated speed orv control position for applying the fluid pressure to any particular gear shifting device 22.

The conduit 3l, leading from the pump to the valve, with the oil chamber of the selector valve andV thence communicates with the particular gear change device through a choke and relief valve 33. The main control valve is also connected through a separate conduit'll. to the choke and relief valve for exhausting the latter and for causing the pumped oil to be delivered through the main control. valve and the choke and relief valve to a lubricating system and thence back to the pump reservoir when the transmission is disconnected and the pump operating.

'I'his choke and relief; valve 33. is provided for causing the pressure of the pumped oil entering aoraosa the selector valve m develop degree sumciently high for creating an impulse for shifting into a resistance coil 3l for retardin'g the movement of the valveas the gearshifting impulse is provided. The retardation of the valve is overa period of time for causing pressure development.

suillcient to eillciently shift the particular gear, and thereafter the choke and relief valve acts to relieve the gear shifting or impulse pressure by shunting the oil to some other source such as the lubricating system from whence the oil may return by gravity to the pump. The choke or relief valve is suitably ported for causing either lthe exhaust or the main supply line thereto controlled by the main valve to be connected to thelubrieating system.

"Therefore, it will be apparent lthat the pump normally operates at low pressure through the control valve and the choke and relief valve 'at all times when the main power shaft is being operated independently of the position' of the clutch, control valve, or choke and relief valve with the exception of the initial phase of ilow when the clutch is thrown in. 'Ijhe necessary high pressure for shifting 'a gear selected by the position of the selector valve only occurs immediately after the control valve is operated by conneeting the main power shaft to the train of gears. This rise in pressure is accomplished by choking the low pressure ow or circuit to the lubricating system at the time that the main supply line or passage -to the selector valve is open.

The fundamentalpurpose of the choke or relief valve is to lower the normal running load on the l pump, this being accomplished by causing'the pump to produce a gear shifting or high press e only at the actual time of gear shift. The now f oil, therefore, from the constantly operated pump, is to the lubricating system alone when the clutch is out. The oil in the selector valve is sure phase, the choke and relief valve functions to relieve or clear the passageway to the lubricating system. The vchoke and relief valve is shifted by the developing gear shifting pressure at a slow rate of speed so that the high pressure developed by this obstruction in the line shifts the gears in the rst phase of valve movement,-

and as the choke valve completes lits movement removing the obstruction in the"M line, the oil flows throughto the lubricatingsystem and the pressure lowers to normal. This low pressure then\ continues to exist in the selector valve for holding the shifted gears in place until the clutch is thrown out and ineagain and the control valve correspondingly shifted.

A safety valve 36 may be provided inthe main supply line leading from the pump to the control valve to eliminate any hazard because of undue high pressure. The resistance for the choke valve may bein the form of a coil of pipe having a small diameter slowly exhausting the fluid so that the high pressure is maintained long enough to effect the gear shift. The moment the clutch is thrown out the choke valve is returned to normal position because ofthe action of the control valve in opening communication between the main 'supply line andthe choke and reliefvalve at the opposite end of the choke and relief valve orv the end previously resistance.

erated detent engaging the rotatable valve element for determining the successive stops of the valve, which stops are indicated on the faceplate of the valve for a visual determination of the speed at which the valve is set. The system in this instance includes a selector valve which controls thirty-two speed changes.- The fluid is admitted to the interior of the valve and passes through a plurality of radial ports which are selectively aligned with ports in the bodyl of the valve extended through conduits to the appropriate shifting devices.

The present valve is highly eillcient and compact in that, for the thirty-two speed changes', it only employs twelve control pipes extending from the selector valve to thevarious devices, which conduits o r lines may be functioning' either as feed lines or exhaust lines in accordance with the arranged system as will be'fully apparent hereinafter. r

In order that the system will not drain over a moderate period of time, a stand pipe 3-1 is provided extending above the level of the devices of the apparatus, this stand pipe being in communi-A cation, through the control valve, with the selector valve andany'particular gear shifting devices which happen to be functioning at the time.

The various gear shifting devices include plungers which are operated in either direction for shifting the gears into the one of two positions desired. Certain of the gear shifting devices are dezigned to control the shifting of particular gears into three positions, the intermediate of which is a baianced or unmeshed position for .the gears.

Furthermore, particularly in the instance of vertical shafts, the ge'ar shift devices include hy-` draulically operated means positively engaging the shift devices. for locking the gears in upper position to prevent dropping of the-gears in the eventA of uid failure, which would be detrimental either in case the transmission is in operation at the time or if the transmission is not in use would cause damage to the gears if. the transmission were started up without inspection thereof.

Inthe instance where two clusters of gears are shifted on the same shaft alternately by corresponding hydraulically operated gear lshifting devices, a mechanical interlock is provided between these devices for preventing the meshing of one cluster of gears when the other cluster is in mesh. The transmission easing and arrangement of gears therein is of no consequence in the present application since the invention is primarily directed to the system and apparatus for shifting gears rather than to the mounting of the gears.

Referring specifically to the drawings, the pump 23 is secured in the extreme lower region of "'the transmission casing within the eompartmentor reservoir 24 thereof. An intake pipe 38 is provided for the pump which pipe extends into the lfluid pool Within the compartment. 'I'he main exhausted through the` 'I'he selector valve includes a hydraulically opi power shaft 25 is journalled within the casing and the pump is located adjacent this power shaft.

Bevel gears (not shown) mounted on the power shaft are alternately connected to the power shaft and transmit the drive through bevel gear 4I in mesh with both of the reversing gears. The bevel gear 4|, which is in mesh with both the reversing gears, is connected to one end of a shaft of the transmissionwhich is the first shaft in the train of gearing and shafting leading to the spindle. The details of this reversing gear mechanism are not disclosed for the reason that it may be of any standard construction.

The lever 26 is mounted in the transmission casing or head of the radial drill, this lever being mounted upon the lower end of control shaft 42 carrying a yoke 43 on its upper end operating the clutch 21. This yoke element includes the device 28 for operating the control valve in the nature of -a cam portion extending in the opposite direction from the fork. This cam is segmental providing two high surfaces generated on a radius taken on the control shaft axes and an intermediate low portion. This cam is in engagement with the l outer end of. the main control valve plunger 29.

The engagement is accomplished by means of a roller 45 mounted in the outer and bifurcated end of the slide valve 29. This valve 29 is spring urged against the cam by means of a spring 45 under compression between the bottom of a socket therein and a closure screw 46 secured in the opposite end of the valve body. The control valve accomplishes the following fluid communications. v

In normal position with the clutch thrown out and the spring effective for moving the plunger outward in engagement with the low spot of the cam, the pump 23 is connected directly to the choke and relief valve and thence through the lubrication line or conduit 41. This is a low pressure condition'during which the pump is not laboring but is forcing oil through an open system returning the oil to the reservoir through the various bearings of the transmission or through a direct return or by-pass. Another fluid communication which is effected at this time is that the stand pipe 31 is in communication with the selector valve for maintaining a solid presence of fluid in the selector valve and in the particular gear shifting devices in operation at the time.,

When the clutch is thrown in and the gear transmission is being operated, the main supply line 30 from the pump is in communication withV the selector valve'and with the choke and relief valve, which communication initially actuates the choke and relief valve. The exhaust end of the delay valve is opened at this time through the control valve to the resistance pipe 35 slowly exhausting the fluid from the rear end of. the choke and relief valve 33.

These various communications established between the piping of the system are accomplished by the following groove and port arrangement in the main control valve 29 and its body 29. The plunger or slide valve 29 includes three annular grooves 48, 49 and 59, spaced along its longitudinal extent. Each of these grooves is of substantial width for effecting continual communication with certain of the respective ports located in the same side ofthe control valve body. The

first of these ports toward the cam engaged end of the plunger has the resistance pipe 35 connected thereto.

'Ihis port for the resistance pipe communicates with the alternate supply-and exhaust pipe u extending to the choke and relief valve, this pipe 34 being connected to the control valveat vthe'.

diametrically opposite side from the resistance pipe port. The communication between this exhaust pipe 34 and the resistance pipe is established through the first groove 48 of the plunger when the transmission is in operation and the plunger depressed.

The supply line or conduit 30 from the pump is connected at all times with a second annular groove 49 of the control valve. At the opposite side, the main supply line Icontinues to the choke and relief valve and the selector valve, this extenson 5| of the supply line being in communication with the groove 49 through a port in the body only when the plunger is depressed and the transmission is in operation. This central groove 49, which is constantly in communication with the supply line 30 from the pump, alternates in position of communication with the supply v rest with the transmission, the groove 50 opens communication between the stand pipe and the supply line continuation 5l to the choke and relief valve and with the selector valve so as to maintain the previously described fluid supply or bodyy within the selector valve and the particular connected shifting device.

The main supply line 5| extends to the selector valve and to a hydraulically operated detent 52 for the selector valve, the flow of the fluid from the selector valve to the particular shifter device Y being accurately maintained by this detent. The supply pipe continuation 5I is also connected to the body of the choke and relief valve 33. The port in this valve 33, to which it is connected, is forked, one of the passageways thereof, namely 53, extending to the valve cylinder at the head end of the plunger and the other opening 54 to a side of the plungerand adapted to communicate through radial ports with a central passageway 55 of the plunger and then .with an annular groove 56 of the plunger, which groove is always in communication with the return or k lubrication line 41.`

Vof the control valve, the fluid passes both into the selector valve and into the head end of the choke and relief valve, the selector valve having previously been set to open communicationV to the appropriate shifting devices. 'I'he rear end of the choke and relief valve at this time is connected to the resistance coil through one fork 59 of'a forked passageway or port for the alternate exhaust and supply pipe 34. Therefore, the

fluid pressure rises as the valve moves slowly against the resistance afforded by the resistance coil. When it reaches the positive abutment provided by a closure screw 33* in the end of the choke and relief valve body, the second fork 59 passageway l5 .of the valve for opening or reliev- V of the supply pipe is connected to the interior ing the fluiddow through to the return or lubrieating line. f l

Thispositiomeectedafterthesearshifthas been accomplished by the rise in pressure through the selector valve, is maintained lmtil the 'clutch is disengaged and the controlvalve returned to normal position. The return of the control valve to normal position establishes communication between the main supply pipe from the pump and the alternate supply and exhaust pipe 3l, closing off the supply to the head end of the choke and relief valve by removal of the central annular groove 49 from communication with the pipe il. Thereupon, the uid flow is directed to the rear end of the choke `and relief valve moving the valve quickly back to a reverse position and exhausting or displacing the fluid at the head end of the choke valve piston out through the stand pipe. Y

With-the choke and relief valve returned to normal position when the transmission is idle,

, communication-is establishedfrom the alternate exhaust or supply line '3 4 through the forked passageway thereof through the interior passageway of the valve plunger and through the central annular groove thereof for return through. lubrication line. The lubrication or return line includes a pressure control ,valve El opening to pressures trom the choke and relief valve and closing when the pump is idle for maintaining a solid supply of uid within the shifting system.

The specific construction of the choke valve plunger or piston for the aforesaid connections includes three annular grooves, the outer groove El-SI of which respectively communicates with forks Y51S, 59, of the inlet passageways ofthe supplylines at .the respective ends ofthe choke e and relief valve body and the intermediate groove 5S constantly registering with the lubricaon line. All of these grooves are interconnected at all times by radial ports and the central pesage 55. Only one of the connections of the lubrication line to a bearing oi' the transmission is shown herein although it will be appreciated that any number may be provided.

The selector valve s2 is of hollow rotatable type -mounted in a body 32a and a hollow rotatable valve element. This valve body is ailxed to the inner wall yof the casing and the-valve includes a shank E6 extending through the wall to the exterior thereof and carrying a manually operable indicator heb 51. The present system includes 32 speed changes so that 32 spds are indicated (not illustrated)arolmd the periphery of. the knob for registry with a stationary indicator element 68 adiacent the periphery. F501'- each of these' different speed indications, the valve has a corresponding aligned notch E! in its opposite end, which notches are engageable by the hydraulically operated detent.

The valve body is hollow providing .a Y

:for dstr'buting the fluid to the appropriate shifti'ng devices. The detent is urged by means of a' spring lo as well as hydraulically urged into reg-- istry with the teeth and'is maintained against rotation by means of a set screw 1l 'engaging a longitudinal slot 12 therein for maintaining registry of a radial port 'I3 extending from the hollow interior of the detent, with a fluid Supply line Il extending from the main supply-line 5|. The detent is subjected to the normal nmning or low -pressure of the pump when the control valve has been shifted andthe clutch thrown in for connecting the power to the transmission.

This positively hydraulically locks the detent inn memmtwlth theappmpriateadjacent notch,

for apartlcular gearshifgto'prevent accidental i displacement tbcreofwhenthegearsaremoving. Whenthecontrolvalveisreleasedandthe tramissimidlathedetmtiluidchamberisin eommunicatlonwiththestandpipethroughthe groove 5I of the control valve permitting easy displacementoftheiluidandrelativelyeasyturningorresettingoftheselectorvalvesincethedetentisonlyresistedbythespring. Theconstant simply connection tofthe selector valve is througharadialportliinthebodythereof communicating with'an'annular groove inthe valveelementandaradialportllinthevalve element extendingtotheinterlorchamberthereof- 4 TheSupplyDol'lStotherespectiveshifngdevices are disposed in novel relation in live. sectional planes taken transversely throughthevalveasindicatedinFiguresZtoG inclusive of the drawings. The iiuid supply is always present in allthe ports but the iiow through the ports is controlled by the position of the valve relave to certain other stationary ports in the valve .body for the various conduits to the shifting devices. ll'hese stationary ports in the valve body flmction both as Supply and exhaust ports. When they flmction as exhaust portsthereturnisnotintothe interiorof the valve element but is controlled by grooves in the outer peripheral surface thereof, which grooves establish communication to the exterior of the valveandretmntheuidbackintothetransmission casing and the reservoir for re-use for the reasonthat thevalveiseontainedwithinthe transmissioncasing. A

Forthepurposeofprogressingtoabetter understanding of the port arrangement within the valve and the circuit of .the iiud new to the shifter devices, a high speed transmission shifted position is illustrated in Figures 1 to 6 inclusive. The rst comiterxshaft 18 ofthe transmission of the one upon which thebevel gearl driven by the reversingv gears is mounted, is a splined shaft. A gear cluster 'I9 is slidably mounted upon ,the splinedshaft a'ndincludestwo gears.- The- 'thesmallestgearofihetwoclustersntheshaft 8 1. Thephmgerisinlowerpositionsothatthe hydraulicsafetydetentoftheshifterdeviceis notfunctioning; 'Iheudsllmlvcircuitfrom the selectorvalvaatthistimejsthmughgwn.

duiteonnectedtoaportintheselectorvalve,

li'igureofthedrawlngs.

Thissupplyconduitextendstotheshifter device body, enteringan annular groove I6 encirclingtheplungerandcmmnunicatingwiththe detent cylinder attheinnerendofthe detent andthencethroughapnssagewayl'lextending bodylyinginthesectiomal plane indicatedin. .I0

cylinder, the plunger being above the entrance' of the passageway prior to the present shifted position for permitting exhaust therethrough and through a conduit 88 communicating with this cylinder and extending to the selector valve body.

.This conduit communicates with an exhaust` groove 89, which groove extends longitudinally in the outer periphery of the valve element into communication with an annular exhaust groove 90 lying alongside of the plane of Figure 6, which constantly communicates with a port 9| extending to the exterior of the valve body. This exhaust passageway arrangement is exemplary of that used for all the exhaust conduits. 'I'he longitudinal grooves similar to 89 are shown in the transverse sectional/ views and the annular grooves similar to 90 are best shown in Figures 1 and 7. f

This position of the shifter device represents the highest speed possible between the two shafts described thus far. It is necessary to the gear shaft arrangement to maintain this position on .the shifting device for four speed changes successively then to mesh the small gear in the cluster on the shaft 18 with the large gear in the upper cluster on the shaft 80 for the next four succeeding gear changes and to thereupon return the large gear into mesh with the small gear etc.

This is accomplished by having the described effective supply line successively register with four supply ports 98* in the valve (see Figure 6) and the exhaust line 88 to communicate with four exhaust grooves 89 successively.

'Ihe next or intermediate shaft in the train is a spindle shaft 92 mounting two independently slidable gear clusters 93, 94, each of which includes two gears. Each of the four gears thus mounted on this shaft is aligned for mesh with a particular component gear of the four gears on the preceding shaft. By placing two shiftable clusters on the third shaft of the train, it is possible to reduce the number of shafts necessary to accomplish the 32 speed changes present here- 1n arrangement. The first shaft drives the second shaft at two speeds and by the four gear ratio variation between the second and third shaft, each of these first two speeds may be converted into four. devices for these two gears which includes a mechanical interlock will be described-later.

The third shaft 92 also carries a third shiftable gear cluster 95 of two gears. The next shaft in the gear trainis a plain shaft 98 upon which shaft one gear cluster 91 and a single gear 98 are pinned. The gear cluster 91 including two gears has its large gear in mesh with the large gear of the upper cluster 95, on the third or splined shaft, when the transmission is in the high speed now, being described. The shifting device 99' for'controlling the shifting of this third cluster 95 on the third shaft is of the same structure as the shifting device previously described. The position, however, is varied for the high speed from that of the preceding shifting device,.

This shifter device is controlled from ports in the sectional l,plane of the selector valve shown in The third shaft 92, therefore, may be driven atk eight diierent speeds through this three shaft A The description of the gear shiftingv Figure 5. The plunger is held in upper position and being a vertical plunger controlling a vertically mounted gear cluster, the hydraulic safety detent is in operation at this position.

The fluid supply to this shifter device is through a supply port |00 in the control valve (see Figure 5) then through a conduit |00 extending to the lower end of the shifting device body or cylinder. Fluid supply to this cylinder raises the plunger 99n effecting the gear shift and at 'the moment that the shift is fully effected, the plunger opens communication to the passageway 88a extending tothe rear of the detent |0| thus forcing the detent into a transverse notch |0|,in the plunger which is exactly oppositely disposed at this position. With the detent within the groove, uid failure may occur behind the detent or below the plunger without disastrous results for the reason that the displacement pressure or gravity acting on the detent is directed at right angles against the detent and no displacement can occur.

The exhaust of the opposite or upper end'of the shifter device takes place through the detent return passageway 81 extending to the upper end of the cylinder ofthe shifter device. It will be seen that prior to the quick setting movement of the detent, this passageway is open to the conduit |02 extending to the sectional plane of Figgure 5 via the forward end of the detent chamber, then through the annular groove 86 about the plunger toexhaustgroove |02a thence through the particular annular -exhaust groove to the exterior of the valve. It will be apparent that the moment the detent is actuated, exhaust for the upper end of the plunger cylinder is no longer necessary and the interruption thereof is of no consequence (see Figure 1).

The detent must always be hydraulically removed from its effective position. 'I'his is done by the use of the upper conduit |02 as a supply conduit, the conversion being effected by the selector valve. The fluid flows through the annular groove into the notch I0|, which notch has a V-shaped base |0|b providing a line engagement with the detent so as to permit ingress of fluid within the notch and against the head of the detent for moving the detent back and out of position (see Figure 14). 'I'he detent at this juncture constitutes a valve which must be displaced from effective position to open fluid supply or communication to the upper cylinder of the shifter device.

The selector valve in controlling this shifter device 99 includes a grouped arrangement of supply ports and exhaust ports which is as follows. For the next eight successive positions of vthe selector valve the described position of the shifter device 99. for meshing the large gear of the upper cluster on the third shaft willoccur since there are eight successive supply ports |00* (see Figure 5) and the exhaust appropriate thereto will also occur because of the eight successive exhaust ports |02. `Then for eight succeeding positions this arrangement will be reversed etc. The reason for this arrangement of ports will be more fully apparent as the description progresses.

Through the third cluster l95 on the third shaft 92 of the transmission, which cluster alternately meshes with a single gear 98 and the large gear of the gear cluster 91 on the fourth shaft, the speed changes are doubled again and therefore it is possible to impart sixteen speeds to the fourth shaft.

Beyond the fourth shaft is aanother splined shaft Il! which'carrlesthe spindle II on its lower end. This ilfth shaft'carries asleeve Land a Sear cluster Iliisslidablykeycdtothesleeveso thatthedriveforthefourthshaftisobtained throughgthis gear cluster to the sleeve and thence to the spindle shaft. The drive to the last Amentioned gear cluster may. either be from the single gear S8 on the preceding plain shaftor from the gear cluster 91 on the'preoeding shaft through a gear' |06 loosely rotatably mounted on the sleeve '.of the iifth shaft and drivlngly connected to the 'fifthshaftbyn'ieansofintermeshcfa'gearill of the cluster of the'flfth shaft with an internal gear llt formed in the loosely mounted gear. The loosely molmted gear is held stationary against longitudinal or axial movement, whereas the gear cluster is shiftable. This gear cluster on the fifth shaft is shifted by means of a shifting device Il!` exactly like those previously described.

In the high speed connection shown in Figures l to 'I inclusive, this shifting device is in its lowermost position or a. position which correspondsidentically with the position of the iirst described device 83 controlling the gear cluster on the first shaft of the transmission.- The control pipes for this shifting device extend to the sectional plane of theselectcr valve, seen in Figure 4 of the drawings, the supply pipe IIB being connected through its supply port HB" to the interior of the valve and the exhaust pipe I I being connected to the exterior oi the valve, through an appropriate exhaust groove HIB similiarly connected for the next sixteen settings or speed changes of the due to the provision of sixteen successive supply ports lilia and the exhaust connection is correspondingly main- Y tained through the provision of sixteen succemive exhaust ports Ilia. Thereupon for the next sixteen vspeed changes the condition is reversed. The drive in this position of the shifting device A takes place through the single gear SB, through the cluster I to the spindle sleeve.

lAt this fth or spindle shaft it is possible to either drive through the cluster 91 on the fourth shaft 96 to the loosely mounted gear thence by way of the internal gear connection to the cluster |6 5-or to drive through the single gear on the fourth shaft in direct connection with the cluster on the fth shaft as shown in Figure l. Therefore, the sixteen changes in the fourth shaft may be doubled at the spindle shaft and thirty-two speed changes accomplished.

Two shifting devices H2, |20,- are used for shifting the clusters`93, 94 on the third-shaft which is the intermediate or central shaft of the tranmission. Each of these shifter devices have their respective plungers connected vto a respective gear cluster 93 or 94 by means of forks similar to those previously described for the remaining shifting devices. The primary difference between the two shifinng devices now being described is that they are shiftable into three posi tions, two of which positions are gear meshing positions and the intermediate of which is aneutrai position. For this'reason the pllmgers are controlled in an entirely different manner.

For the purpose of the high speed transmission connection, shown in Figure' l,v the uppermost gear cluster is moved to mesh the smallest gear thereon with the largest gear on the preceding shaft whereas the lowermost gear cluster is in neutral or unmeshed position. In thisposition the plunger II!I of the upper gear shifting device |I2 is elevated. 'I'he coxduits forcontrolling these two shiftingdevicesextend from the sectional planes of the valve indicated in Figures 2 and 3. For the shifting device eifecting the gear shift or gear connection, a conduit IIS extends from the sectional plane of Figure 2 of the selector valve for the supply to the cylinder below the plunger H21; this conduit being connected to the detent and moving the same into the Vadjacentlv disposed slot or notch IIG of the plunger.

Two other conduit'connections to this shifting device are provided for properlyexhausting the same at this time. One of these, namely lll, extending to the sectional plane of Figure 2 of the valve, permits exhaust from the bore in front of the detent through an annulalr groove ||8 about the'plunger adjacent the detent so that the detent may be set within the groove,- this exhaust taking place through the vselector valve body throughan appropriate longitudinal groove H1B. The other exhaust conduit I I5 is connected to the upper cylinder of the shifter device via a passageway I2I, through the detent cylinder and thence to an exhaust grcove IIS of the selector valve in the sectional plane of Figure 3.` Another exhaust line or passageway |22 connects to this conduit at the extreme lower end of the cylinder below the plungerA for the following purpose.

The plunger control cylinders at the respective en ds of the plunger each include a iioating piston |23 which may be termed balancing pistons. This latter conduit 9, at this time, exhausts the region below the lower floating piston, and the region above the upper floating piston. i

The other shifting device |20, identical to th Yone just described, engages the second cluster of gears on the intermediate or third shaft and is in balanced or neutral position at this time. Balancing of the plunger ILP1 for maintaining the same inv intermediate position is accomplished by introducing fluid pressure above and below the respective balancing pistons and exhausting the opposite regions adjacent these balancing pistons. Therefore, a conduit |24 extends from a supply port |245 second in the sectional plane of Figure 3 of the drawings of the selector valve to this shifter device |20 and is connected throughV tending to the lowermost point of the lower cylinder below the balancing piston, and the other Prior to this balanced condition (assuming the shifting device I2l, presently considered, to have been in uppermost positionithe detent thereof was forced from the notchv in the plunger by 1 the application of iuid pressure, through the dethe selector valve from an annular groove I I surrounding the plunger adjacent the detent. 'I'his annular groove is connected to the upper cylinder below the balancing piston by a passageway |21 extending parallel with the plunger to the detent chamber. The fluid above the lower balancing piston is exhausted out through another conduit |28 extending to an exhaust port H1IL in the sectional plane of Figure 2 of the selector valve. This last exhaust also includes the cylinder housing the plunger at its lowerk end since to neutralize or balance the piston or plunger it is necessary for the balancing pistons and plunger |20 to move simultaneously into engagement, the upper balancing piston accomplishing the downward movement of the plunger and the fluid pressure being exerted under the lower balancing piston to raise the same. These balancing pistons move between defined limits represented by the ends of their respective cylinders and in balanced position; each engages the respective adjacent ends of their cylinders and the opposite ends of the plunger. The balancing pistons have their ends annularly grooved as at |29 at the corners to provide ingress for the fluid when the pistons are .against the ends of their cylinders.

In order, to .prevent accidental shifting, due to oil failure, of one of the gear clusters 93, 94, on the intermediate shaft 92 when the other cluster is in mesh, a mechanical interlock is provided which is associated with the respective shifting devices ||2, |20, controlling these clusters. .The shifting devices are located-about the intermediate shaft at circumferentially spaced positions as it will be seen by the indication of the'respective plunge'rs H2 and |20* thereof in Figure 15 of the drawings. These shifting devices are mounted upon a bracket |30 supported within the casing (the support means not being shown herein).

'I'he shifting yokes |3|, |32, which are keyed to the respective plungers H2", |20, each carry control plates |33, |34. These plates 'are bolted at their upper and lower ends respectively to the respective yokes. Slide rods |35, |36 are secured longitudinally through the plates and are slidably mounted in the bracket |30 for the shifter devices. 'Ihe plates carried by the respective shifting yokes have adjacent edges in slidable contact. The interlock element co-acting with these plates is in the form of a rotatable disc |31 mounted in a vertical-rib |30 of the Y support bracket. 'I'his interlock element includes a trunnion |39 for the aforesaid mounting.

The rear of the control plate |34 includes a semicircular groove |40, the center of which lies on the adjacent edges of the respective plates. The disc includes a semicircular -rib |4| also taken' on a center registering with the abutting edges of the plates, this rib being of the same dimensions` as the aforesaid groove for registry therewith. The disc is connected to the other plate |33, the connection being by means of a' pin |42 extending through the plate and its guide rod and projecting from the rear thereof into a radial slot |43 in the interlock disc. Therefore,

reciprocation of the plate |33 as brought about bythe hydraulically operated shifter yoke, rotates the interlock disc when there is no interference.. However, it is provided that the ends ,|44 of the semicircular lug or "rib which lie upon a diametrical line, abut the adjacent face of the unattached or adjacent plate.

The only point at which rotation of the disc shifting devices is in position for meshing gearssince the centers of the rib and groove are out of registry.

The yoke |32 at the left hand side of the view has been shifted downwardly from a neutral position to mesh appropriate gears. At this point, it is impossible to move the other shifting yoke since its plate is connected with the rotatable disc and the rotatable disc is held against rotation by the abutment of the ends of its rib with the side face of the shifted plate. Therefore, before this locked plate |33 can be shifted from its neutral position, it., isnecessary to raise the other plate by an appropriate shift of the shifting device to neutral for registering the centers.

The same thing Will occur when the plate |34 or yoke |32 at the left hand side of the view is raised to carry its groove center above the center oi' generation of the rib. Thus it is impossible to cause mesh of both gear clusters with their component gears simultaneously. For example, assuming both the shifting devices to be in neutral, if there should occur a fluid failure it is obvious that the hydraulic detents will not function to prevent falling of the gears and intermesh of both clusters with their companion or component gears. This, however, cannot occur for the mechanical device just described would necessitate that either one or the other of the plates take preference for movement; that is to say, either the rib must move within the semicircular groove to permit movement of the plate connected to the ribbed disc, or the other plate must move to carry the center of generation of its groove out of registry with the center of generation of the rib of the'disc.

The successive positions of the selector valve accomplish the following settings or arrangements of the shifter devices for the various speeds of the transmission. This description is given of the intermediate positions of the selector valve and gears preparatory to an understanding of the extreme low speed of the transmission as represented in Figures 1 to l2 inclusive.

As will be apparent from the sectional view of the valve, as shown in Figure 6, and the preceding description, the gearA cluster 19 on the first shaft 18 of thetrain is maintained in a given position meshing one gear thereof for four successive settings of the selector valve and thereupon it is shifted for "meshing its other gear for the next four succeeding shifts.

During the first four shifts starting from the extreme high speed, the shifting device con' trolling the uppermost cluster 95 on the intermediate shaft 92 is stationary as will be apparent from Figure 5 illustrating the sectional plane "of the valve wherein the ports are located for controlling this shifter device. The successive arrangement of the supply ports |00a and exhaust ports |02* is such that this shifted position will be maintained for eight successive valve positions or speed changes, but for a consideration of the. same with the shifting movements of the gear cluster on the first shaft, only thefirst four of these changes will be regarded. A

l shifting devices will therefore be stationary for cessive arrangement of ,supply ports H* and exhaust ports in the sectional pla'ne indicated in Figure 4.

While these fourvsuccessive settings oi.' the se` lector valve are being made, the three mentioned of the pair of gear clusters on the intermediate Shaft.v

Now it occurs that' upon vthe mth shift starting the next four shifts, Vthe i'irst shifting device controlledfby the-porting in the plane of .Figure is reversed and the cycle is the same for the next `four in regard to the shifting of the pair of. gearclusters on the intermediate shaft, the remainder of the shifter devices beingV maintained in set position. For the next eight speed changes, the same cycle described up to this point or for the first eight is `repeated with the exception that the. shifting device moving the third gear cluster on the intermediate shaft maintaining the original position. 'I'he variouss\ is reversed for changing the gears at this point.

speed changes during this time will be accomplished by the -pair of shifting devices-H2, |20..

or balanced position, is also maintained in position by the relation of the supply ports |24* and exhaust ports I9" in the plane of Figure 3 which control the balanced position of this shifting device |20; that is to say, two supply ports |24l register successively with the supply conduit to the balancing chambers of this vshifter device while two exhaust ports IIS* register successively with the exhaust conduit'on this shifting device. Therefore, `for the four successive positions now beingconsidered, the ilrst two settings balance the shifting device |20 and the next two', reversing the ports, balance the shifting device 2.

The arrangement in the plane of Figure 2 provides three exhaust ports H1'L between each supply port H3. The conduit ||3 leading from the lower end of the shifting device ||2, being actuated for this second setting, registers with an exhaust conduit I l1* and the detent displacing conduit is connected to a supply port llirthereby permitting the gears to move into lower position. At the next or third position, the position of the lower shifter device |20 is changed and the v previously operating shifting device |20 is moved to balanced or neutral position.

It will be apparent that the ports disclosed in Figure 3 control only the balancing conduits H9,

|24, reversely exhausting and supplying the same after each two succeeding settings of the selector valve. Therefore, the third setting results in a reversal of the balancing of these shifting devices ||2, |20.,and the lower of these shifting devices '|20 is then moved to shift its gear cluster 9|.

'lhe conduits which control this lower device |20 now function as follows: a Supply port I3 Y of the selector valve registers with the conduit |20 which supplies the iluid to the underside of the plunger raising the 'gear cluster to mesh itsV upper gear and also operating the detent. V'The other conduits |20, |26, are then connectedto exhaust ports ll'l.

For the foln'th position the ports in the bal- Thus the Yfou'r men-VV /e/when the sixteenth speed change has been.

ched, the shifter device controlling the shift- Y of the gears on the spindle shaft is reversed dueto the` movement of the valve past the sixteenth successive supply port in the plane controlling this shifter device.. Therefore. for the next sixteen speed changes, the cycle is the same as for the rst sixteen shifts'with the effectv that the change is accomplished solely due to the change of gear mesh onA the spindle. shaft.

. 'Ihe last speed, which is'the thirty-second speed, has been fully illustrated in Figures 'I to 12 and will not be described specifically inasmuch as it is believed that it will be understood from Athe description given, th'e conditions existing being that the positions of the shifting devices 83, 99 and |09 are reversed from the postions described in reference to the high speed and the pair of shifting devices ||2, |20 controlling the gear clusters onthe intermediatev shaft are reversed as'to neutral position. A A modified form of lubricant supply means is illustrated in Figure 17. 'I'he device consists of a cylinder immersed in the fluid, a piston |5| in the' cylinder, a uid supply line |52 `adapted to extend from the cylinder to the control valve including a choke valve |53 opening to permit outow upon the forward stroke of the piston and an intake port |50 also controlled by a choke valve |55 which opens to back stroke of the piston and closes to discharge or supply stroke. The piston may be hand operated by means of a lever |55 for pumping up the fluid.

supply in the system, or may be used. to impartan impulse or high pressure at the moment that the gear shift is to 'be effected. Assuming the entire system to be lled compactly with fluid,

the pumping of additional viuid into the same y will be eii'ective for operating the choke-and relief valve in the same manner described in relation'to the continuouslyvoperating pump for a high pressure impulse.

Having described our invention, we claim:

1. A hydraulic gear shifting system for changingthespeedgearswithinaradialdrillhead including vertically disposed shafts for the gears; comprising, hydraulically operated shifting devices, each mounted adjacent the respective'gear which it shifts, selective means for directing. the hydraulic pressure to a'. 'particular shifting device, and entirely hydraulically operated locking means within each shifting. devicefor sustaining the' shifting devices in upper po-` sitions against the influence of gravity in the event of fluid failure.

2.V A hydraulic gear shifting system for changing gears mounted on vertically disposed shafts,

comprising, a iiuid pressure means, hydraulically operated shifting plungers, each .mounted adjacent the respective gears which itshifts, conselector valve having respective conduits ex tending to the various shifting devices, means for manually setting said selector valve, a supply conduit extending from the pump to said selector valve, a control valve interposed in said latter conduit, means forv operating said control valve for admitting or exhausting the fiuid to or from saidselector valve, a iluid return conduit extending from the supply conduit to the pump, and a choke and relief valve inserted in said return conduit, said choke and relief valve adapted to build up the pressure within the supply conduit and selector valve at the time of shifting and automatically relieving the high pressure when the shifting has been accomplished.

4. In combination with a plurality of gear sets to be shifted, a fluid pump, a hydraulically operated shiftingdevice for each set of gears, a selector valve having respective conduits extending to the various shifting devices, means for manually setting said selector valve, a supply conduit extending from the pumpto said selector valve, a return conduit extending from the fluid supply conduit to the pump, and a choke and relief valve inserted in the return conduit, said choke and relief valve adapted to build up the pressure within the supply conduit and selector valve at the time of shifting and automatically relieving the high pressure when the shifting has been accomplished.

5. In a system of the class described, a gear transmission, a power shaft, a clutch for connecting said power shaft to said transmission in.- cluding a lever for shifting the clutch, a fluid pump driven from said power shaft and in constant transmission connection therewith, a selector valve connected to said fluid pump, a control valve located in the connection between the pump and selector valve, means associated with the clutch control for controlling the flow of fluid to the selector valve coincidentally with the operation of the clutch, a plurality of connections extending from the selector valve, shift- .ing devices connected to said selector valve by the aforesaid connections, said devices engaging respective slidably gears of the transmission, and a hydraulically operated detent engaging the valve element at each set position thereof for locking the same against displacement.

6. In a hydraulic gear shifting system, including. shiftable gears, a source of fluid pressure, .a

' selector valve, a shifting device for each shiftable gear, said valve including means for positioning the valve for directing the fluid pressure flow to the desired shifting device, a uid return line extendingfrom the supply line, and an impedance in the return line for raising the pressure in the selector valve at the time of gear shift.v

,j 7. A hydraulic apparatus for shifting the gears of a transmission, comprising, means for placing the fluid under pressure, a supply conduit extending from said means, a control valve located in l said supply conduit, a choke and relief valve located in the supply conduit beyond the control valve, two supply conduits extending between the control valve and the choke and relief valve, a

selector valve located in one of said conduits. a

shifting plunger for each set of shiftable gears, conduits extending from the selector valve to the respective shifting plungers, a plunger located within the choke and relief valve and moving in reverse directions depending on the application of fluid pressure through the respective conduits extending to the choke and relief valve, a resistance conduit extending from the control valve, a return .conduit extending from the choke and relief valve back to the means for supplying pressure, said choke and relief valve provided with passageways alternately connecting the respective conduits extending thereto to the return passageway, whereby said control valve in one position directs the fluid flow through the selector' valve to one end of the choke and relief valve for forcing the same against the slowly relieved uid in direct connection with the resistance conduit and upon completion of the plunger stroke relieves the flow through the return passage to the means for supplying pressure, and which in its -other position opens the other passageway for reversing the piston in the choke and relief valve.

8. In a hydraulic gear shifting system, a source of uid pressure, a control valve connected to said source of pressure, a selector valve connected to said control valve, a stand pipe connected to connected to said selector valve, and means for moving said control valve to alternately connect the selector valve to theuid supply and to the v stand pipe.

9. Selective gear shifting device control means, comprising, a valve body, a source of uid supply connected to said body, a rotatable valve element in said body, a series of circumferential arrangements of conduits extending from said body to the respective shifting devices to be supplied and exhausted, said rotatable valve element having a series of ports, in connection with the supply source, arranged in planes corresponding to the planes of the discharge and supply conduits, and exhaust passageways extending longitudinally from various of said ports in the periphery of said rotatable valve element, said body including exhaust ports located in planes adiacent the planes of the ports of the body and rotatable valve element, and said rotatable valve element including a circumferential groove registering with the exhaust ports and connected to the exhaust passageways, whereby various registrations of ports and conduits may be accomplished for alternate supply and exhaust of the respective conduits.

10. A gear shifting device, comprising, a plunger carrying a shifting yoke engaging a shlftable gear. a body slidably containing said piston, a balancing piston at each end of said plunger, respective cylinders for said pistons formed in the body, said pistons of larger diameter than the plunger, a

'fluid connection to both cylinders at the outer ends thereof for movingthe plunger to balanced or intermediate position upon application of fluid moving the pistons tothe inner ends of their cylinders, and passageways to the inner ends of the respective cylinders for alternately spreading a respective piston and plunger and moving the opposite piston to the outer end of its cylinder.

11. A gear shifting device, comprising, a plunger engaging a shiftable gear, a body slidably containing said plunger, a balancing piston at each end of the plunger in the body, fluid means for engaging both pistons simultaneously against the plunger forv balancing the same, and means for shifting the plunger by direct fluid application to one or the other of its respective ends coinciden- -the control valve, a plurality of shifting devices tally with exhaust of the balancing piston cyl# inders. g v

12. A selector valve for controlling pressure flow to hydraulically operated devices, comprising, a body, a hollow rotatable valve in said body, a fluid supply conduit connected to said body and to the periphery of said rotatable valve e1ement,vsaid rotatable valve element including a groove in registry with the conduit connection and a radial port extending to its interior, said valve body and rotatable element having registrable radial ports for directing the fluid pressure to the various hydraulically operated devices, a detent engaging the end of the rotatable valve element, and said uid supply passageway connected'to the rear side of the detent for forcing the same against the rotatable valve element.

13. A hydraulic gear shifting system for shifting slide gears on their shafts, comprising, a hydraulically operated shifting plunger connected to the slide gears, a fluid pressure means for said hydraulically operated plunger, and a hydraulically operated locking detent adapted to maintain the shifted plunger in shifted position in the event of fluid failure. v

14. A hydraulic gear shifting system for shifting slide gears on their shafts, comprising, a hydraulically operated shifting plunger connected to the slide gears, a fluid pressure means for said shifting plunger, a locking detent adapted to main- 

